Medical image processing apparatus and medical observation system

ABSTRACT

A medical image processing apparatus includes: a superimposed image generation unit configured to generate a superimposed image by superimposing a subject image and a fluorescent image in areas corresponding to each other; a determination unit configured to determine whether or not at least one of a subject and an observation device moves from timing before timing at which one of the subject image and the fluorescent image is captured to the timing; and a superimposition controller configured to cause the superimposition image generation unit to prohibit a superimposition in an area of at least a part of the subject image and the fluorescent image when the determination unit determines that at least one of the subject and the observation device moves.

CROSS-REFERENCE TO RELATED APPLICATION

The present application claims priority to and incorporates by referencethe entire contents of Japanese Patent Application No. 2018-133374 filedin Japan on Jul. 13, 2018.

BACKGROUND

The present disclosure relates to a medical image processing apparatusand a medical observation system.

In the related art, a medical image processing apparatus which capturesan image of a subject to generate a subject image and a fluorescentimage, and is connected to an observation device has been known (forexample, see JP 2016-022325 A).

Here, the subject image is an image obtained by irradiating the subjectwith white light or the like and capturing a subject image reflectedfrom the subject. Further, the fluorescent image is an image obtained byirradiating the subject with near-infrared excitation light or the like,exciting a drug accumulated in a lesion part in the subject, andcapturing the fluorescent image emitted from the subject.

Then, the medical image processing apparatus (image processingprocessor) described in JP 2016-022325 A acquires the subject image andthe fluorescent image from the observation device (an insertion unit andan imaging unit), and generates a superimposed image by superimposingthe subject image and the fluorescent image in areas corresponding toeach other. The superimposed image is displayed on a display device. Adoctor recognizes the lesion part by checking the superimposed imagedisplayed on the display device, and treats the lesion part.

SUMMARY

When timing at which the subject image is imaged (hereinafter, referredto as first timing) and timing at which the fluorescent image is imaged(hereinafter, referred to as second timing) are different from eachother, the subject or the observation device moves, such that thesubject at the first timing and a position of the observation device andthe subject at the second timing and the position of the observationdevice are different from each other.

In such a case, the corresponding observed regions of the subject imageand the fluorescent image are shifted from each other. For this reason,there is a possibility that a doctor may recognize, as a lesion part, asite at which no lesion part is actually present, from the superimposedimage displayed on the display device. That is, there is a problem inthat the convenience may not be improved.

According to one aspect of the present disclosure, there is provided amedical image processing apparatus connected to an observation devicethat generates a subject image by capturing the subject image reflectedfrom a subject and generates a fluorescent image by capturing afluorescent image emitted from the subject at different timing from thesubject image, the medical image processing apparatus including: asuperimposed image generation unit configured to generate a superimposedimage by superimposing the subject image and the fluorescent image inareas corresponding to each other; a determination unit configured todetermine whether or not at least one of the subject and the observationdevice moves from timing before timing at which one of the subject imageand the fluorescent image is captured to the timing; and asuperimposition controller configured to cause the superimposition imagegeneration unit to prohibit a superimposition in an area of at least apart of the subject image and the fluorescent image when thedetermination unit determines that at least one of the subject and theobservation device moves.

According to another aspect of the present disclosure, there is provideda medical image processing apparatus connected to an observation devicethat generates a subject image by capturing the subject image reflectedfrom a subject and generates a fluorescent image by capturing afluorescent image emitted from the subject at different timing from thesubject image, the medical image processing apparatus including: asuperimposed image generation unit configured to generate a superimposedimage by superimposing the subject image and the fluorescent image inareas corresponding to each other; a determination unit configured todetermine whether or not at least one of the subject and the observationdevice moves from timing before timing at which at least one of thesubject image and the fluorescent image is captured to the timing; and anotification controller configured to notify a notification device ofinformation indicating the motion when the determination unit determinesthat at least one of the subject and the observation device moves.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a diagram illustrating a configuration of a medicalobservation system according to a first embodiment;

FIG. 2 is a block diagram illustrating a configuration of a camera headand a control device;

FIG. 3 is a diagram illustrating an example of first and second motionamount calculation processing;

FIG. 4 is a diagram illustrating an example of the first and secondmotion amount calculation processing;

FIG. 5 is a diagram illustrating an example of the first and secondmotion amount calculation processing;

FIG. 6 is a flowchart illustrating an operation of the control device;

FIG. 7 is a diagram illustrating a concrete example of an imagedisplayed on a display device;

FIG. 8 is a flowchart illustrating an operation of a control deviceaccording to a second embodiment; and

FIG. 9 is a diagram illustrating a concrete example of an imagedisplayed on a display device.

DETAILED DESCRIPTION

Hereinafter, a mode (hereinafter, “embodiment”) for carrying out thepresent disclosure will be described with reference to the drawings. Itis to be noted that the present disclosure is not limited to embodimentsto be described below. Further, in the description of the drawings, thesame reference numerals are attached to the same parts.

First Embodiment

Schematic Configuration of Medical Observation System

FIG. 1 is a diagram illustrating a configuration of a medicalobservation system 1 according to a first embodiment.

The medical observation system 1 is used in medical fields and is asystem for observing a subject such as an inside of a living body. Asillustrated in FIG. 1, the medical observation system 1 includes aninsertion unit 2, a light source device 3, a light guide 4, a camerahead 5, a first transmission cable 6, a display device 7, a secondtransmission cable 8, a control device 9, and a third transmission cable10.

In the first embodiment, the insertion unit 2 is constituted by a rigidendoscope. That is, the insertion unit 2 has an elongated shape, inwhich the whole thereof is rigid, or a part thereof is soft and theother part thereof is rigid, and is inserted into a living body. Theinsertion unit 2 is provided with an optical system which is constitutedby one lens or a plurality of lenses and condenses light (subject imageor fluorescent image) from a subject.

The light source device 3 is connected to one end of the light guide 4,and supplies light for illuminating the inside of the living body, toone end of the light guide 4 under the control of the control device 9.In the first embodiment, the light source device 3 includes an LED thatemits white light (normal light) and a semiconductor laser that emitsnear-infrared excitation light in a near-infrared wavelength region.Then, under the control of the control device 9, the light source device3 alternately supplies white light and near-infrared excitation light ina time division manner as light for illuminating the inside of theliving body. In the first embodiment, the light source device 3 isconfigured separately from the control device 9, but the firstembodiment is not limited thereto, and a configuration provided insidethe control device 9 may be adopted.

One end of the light guide 4 is detachably connected to the light sourcedevice 3 and the other end of the light guide 4 is detachably connectedto the insertion unit 2. The light guide 4 transmits light (white lightor near-infrared excitation light) supplied from the light source device3 from one end to the other end and supplies the light to the insertionunit 2. The light supplied to the insertion unit 2 is emitted from adistal end of the insertion unit 2 and irradiated into a living body.When the white light is irradiated to the living body, the subject imagereflected from the living body is condensed by the optical system in theinsertion unit 2. In addition, when the near-infrared excitation lightis irradiated to the living body, a drug such as indocyanine greenaccumulated in a lesion part in the living body is excited, and afluorescent image emitted from the living body is condensed by theoptical system in the insertion unit 2

The camera head 5 is detachably connected to a proximal end (eyepieceportion 21 (FIG. 1)) of the insertion unit 2. The camera head 5 capturesthe subject image or the fluorescent image condensed by the insertionunit 2 under the control of the control device 9, and outputs an imagesignal (RAW signal) by the capturing. The image signal is, for example,an image signal of 4 K or more.

A detailed configuration of the camera head 5 will be described below.

The insertion unit 2 and the camera head 5 described above correspond toan observation device 100 (FIG. 1).

One end of the first transmission cable 6 is detachably connected to thecontrol device 9 via a connector CN1 (FIG. 1), and the other end thereofis detachably connected to the camera head 5 via a connector CN2 (FIG.1). The first transmission cable 6 transmits the image signal or thelike output from the camera head 5 to the control device 9 and transmitsa control signal, a synchronization signal, a clock, power and the like,which are output from the control device 9, to the camera head 5.

The image signal or the like from the camera head 5 to the controldevice 9 via the first transmission cable 6 may be transmitted as anoptical signal or an electrical signal. The transmission of the controlsignal, the synchronization signal, and the clock from the controldevice 9 to the camera head 5 via the first transmission cable 6 is alsothe same.

The display device 7 is constituted by a display using a liquid crystalor organic electro Luminescence (EL) or the like, and displays an imagebased on a video signal from the control device 9 under the control ofthe control device 9.

One end of the second transmission cable 8 is detachably connected tothe display device 7 and the other end of the second transmission cable8 is detachably connected to the control device 9. The secondtransmission cable 8 transmits the video signal processed by the controldevice 9 to the display device 7.

The control device 9 corresponds to the medical image processingapparatus. The control device 9 is configured to include a centralprocessing unit (CPU) and the like, and collectively controls theoperation of the light source device 3, the camera head 5, and thedisplay device 7.

A detailed configuration of the control device 9 will be describedbelow.

One end of the third transmission cable 10 is detachably connected tothe light source device 3 and the other end thereof is detachablyconnected to the control device 9. The third transmission cable 10transmits the control signal from the control device 9 to the lightsource device 3.

Configuration of Camera Head

Next, a configuration of the camera head 5 will be described.

FIG. 2 is a block diagram illustrating a configuration of the camerahead 5 and the control device 9.

In FIG. 2, for convenience of explanation, the connectors CN1 and CN2between the control device 9 and the camera head 5 and the firsttransmission cable 6, and connectors between the control device 9 andthe display device 7 and the second transmission cable 8, and connectorsbetween the control device 9 and the light source device 3 and the thirdtransmission cable 10 are not illustrated.

The camera head 5 includes a lens unit 51, an imaging unit 52, and acommunication unit 53, as illustrated in FIG. 2.

The lens unit 51 is configured using one lens or a plurality of lenses,and forms the subject image or the fluorescent image condensed by theinsertion unit 2 on an imaging surface of the imaging unit 52.

The imaging unit 52 captures the subject image or the fluorescent imageunder the control of the control device 9. Although not specificallyillustrated, the imaging unit 52 includes an image sensor such as acharge coupled device (CCD) or a complementary metal oxide semiconductor(CMOS) that receives the subject image or the fluorescent image formedby the lens unit 51 and converts the subject image or the fluorescentimage into an electrical signal (analog signal) and a signal processingunit that performs signal processing on the electrical signal (analogsignal) from the image sensor to output the image signal (RAW signal(digital signal)).

The communication unit 53 functions as a transmitter that transmits theimage signal (RAW signal (digital signal)) output from the imaging unit52 to the control device 9 via the first transmission cable 6. Thecommunication unit 53 is constituted by, for example, a high-speedserial interface that performs communication on an image signal with thecontrol device 9 at a transmission rate of 1 Gbps or more via the firsttransmission cable 6.

Configuration of Control Device

Next, a configuration of the control device 9 will be described withreference to FIG. 2.

As illustrated in FIG. 2, the control device 9 includes a communicationunit 91, an image processing unit 92, a display controller 93, a controlunit 94, an input unit 95, a notification unit 96, and a storage unit97.

The communication unit 91 functions as a receiver that receives theimage signal (RAW signal (digital signal)) output from the camera head 5(communication unit 53) via the first transmission cable 6. Thecommunication unit 91 is constituted by, for example, a high-speedserial interface that performs communication on an image signal with thecommunication unit 53 at a transmission rate of 1 Gbps or more.

The image processing unit 92 processes the image signal (RAW signal(digital signal)) that is output from the camera head 5 (communicationunit 53) and received by the communication unit 91 under the control ofthe control unit 94. As illustrated in FIG. 2, the image processing unit92 includes an image memory 921, a motion amount calculation unit 922, anoise reduction (NR) processing unit 923, and a superimposed imagegeneration unit 924.

The image memory 921 sequentially stores an image signal (RAW signal(digital signal)), which is output from a camera head 5 and received bya communication unit 91, for each frame by a predetermined number offrames. That is, the image signal (captured image for a predeterminednumber of frames) corresponding to a predetermined number of framesstored in the image memory 921 is sequentially rewritten to the capturedimage newly captured by the camera head 5.

In the following, for convenience of explanation, among the capturedimages captured by the camera head 5 (imaging unit 52), a captured imageobtained by capturing a subject image is described as a subject image,and a captured image obtained by capturing a fluorescent image isdescribed as a fluorescent image.

The motion amount calculation unit 922 performs first and second motionamount calculation processing.

Here, in the first motion amount calculation processing, a subject image(hereinafter, referred to as a current subject image) which is outputfrom the camera head 5 and received by the communication unit 91 isstored in the image memory 921, and a subject image (hereinafter,referred to as an immediately previous subject image) captured by thecamera head 5 two frames before is assumed as a first processing target.Here, when among the subject image and the fluorescent image alternatelycaptured by the camera head 5, only the subject image is viewed, theimmediately previous subject image is the subject image immediatelybefore the current subject image in time series. That is, the firstprocessing target is two subject images consecutive in time series.Then, in the first motion amount calculation processing, the motionamount (hereinafter, referred to as a first motion amount) from theimmediately previous subject image is calculated for each region (eachpixel in the first embodiment) in the current subject image.

In addition, in the second motion amount calculation processing, afluorescent image (hereinafter, referred to as a current fluorescentimage) which is output from the camera head 5 and received by thecommunication unit 91 and a fluorescent image (hereinafter, referred toas an immediately previous fluorescent image) which is stored in theimage memory 921 and captured by the camera head 5 two frames before areassumed as a second processing target. Here, when among the subjectimage and the fluorescent image alternately captured by the camera head5, only the fluorescent image is viewed, the immediately previousfluorescent image is the fluorescent image immediately before thecurrent fluorescent image in time series. That is, the second processingtarget is two fluorescent images consecutive in time series. Then, inthe second motion amount calculation processing, the motion amount(hereinafter, referred to as a second motion amount) from theimmediately previous fluorescent image is calculated for each area (eachpixel in the first embodiment) in the current fluorescent image.

Then, the motion amount calculation unit 922 outputs signalscorresponding to the first and second motion amounts to the control unit94.

FIGS. 3 to 5 are diagrams for describing an example of the first andsecond motion amount calculation processing. Specifically, FIG. 3 is adiagram in which subject images CS1 and CS2 and fluorescent images CF1and CF2 alternately captured by the camera head 5 are arranged in timeseries (in the direction of the arrow t). Here, light (a subject imageor a fluorescent image) condensed in the insertion unit 2 has asubstantially circular cross section. Therefore, a subject image SI inthe subject images CS1 and CS2 has a substantially circular shape asillustrated in FIG. 3. The same goes for a fluorescent image FI in thefluorescent images CF1 and CF2. That is, the subject images CS1 and CS2include the subject image SI and a mask area MA (represented by obliquelines in FIGS. 3 and 4) other than the subject image SI. Similarly, thefluorescent images CF1 and CF2 include the fluorescent image FI and themask area MA other than the fluorescent image FI. In addition, FIGS. 4and 5 are diagrams corresponding to FIG. 3 and illustrate a currentsubject image CSC (current fluorescent image CFC).

For example, as illustrated in FIGS. 4 and 5, the motion amountcalculation unit 922 executes the first and second motion amountcalculation processing using a block matching method.

Specifically, the motion amount calculation unit 922 executes the firstmotion amount calculation processing using the block matching method asdescribed below.

The motion amount calculation unit 922 selects a pixel of interest PI(FIG. 4) among all pixels in an immediately previous subject image CSB(FIG. 4). In addition, the motion amount calculation unit 922 selects apixel group Gr (FIG. 4) that includes the pixel of interest PI and aplurality of surrounding pixels PS (FIG. 4) located around the pixel ofinterest PI. In the example of FIG. 4, the number of surrounding pixelsPS is eight (the number of pixel groups Gr is nine of 3×3), but thenumber is not limited to eight, and other numbers (for example, thenumber of surrounding pixels PS may be 24 (the number of pixel groups Gris 25 of 5×5)).

Next, the motion amount calculation unit 922 specifies a pixel group Gr′(FIG. 4) having the highest correlation with the pixel group Gr over theentire region of the current subject image CSC. Then, the motion amountcalculation unit 922 calculates, as a motion vector B (FIG. 4) of apixel of interest PI′, a vector from the pixel of interest PI located atthe center of the pixel group Gr in the immediately previous subjectimage CSB to the pixel of interest PI′ located at the center of thepixel group Gr′ in the current subject image CSC.

The motion amount calculation unit 922 sequentially executes theprocessing described above while changing the pixel of interest PI forall the pixels in the immediately previous subject image CSB, and as aresult, as illustrated in FIG. 5, the motion vector B for each pixel(pixel of interest PI′) in the current subject image CSC is calculated.In FIG. 5, the direction (motion direction) in the motion vector B isrepresented by an arrow, and a size of the motion vector B (motionamount (first motion amount)) is represented by a length of an arrow.The motion vector B represented by a point indicates that the motionamount (first motion amount) is zero.

The second motion amount calculation processing is different from thefirst motion amount calculation processing only in that the processingtarget is changed from the first processing target (immediately previoussubject image CSB and current subject image CSC) to the secondprocessing target (immediately previous fluorescent image CFB (FIG. 4)and current fluorescent image CFC (FIGS. 4 and 5)).

The first and second motion amount calculation processing are notlimited to the block matching method described above, and other methods(for example, a gradient method) may be used.

In the current subject image CSC, the NR processing unit 923 applies atime filter to an area other than the motion area specified by thecontrol unit 94 and applies a spatial filter to the motion area toperform noise reduction (NR) processing of removing random noise fromthe current subject image CSC. Similarly, in the current fluorescentimage CFC, the NR processing unit 923 applies the time filter to thearea other than the motion area specified by the control unit 94 andapplies the spatial filter to the motion area to perform the noisereduction (NR) processing of removing random noise from the currentfluorescent image CFC.

The superimposed image generation unit 924 generates a superimposedimage by superimposing, between corresponding areas (pixels) in all theregions, the subject image and the fluorescent image which are subjectedto the NR processing and are consecutive in time series. Then, thesuperimposed image generation unit 924 outputs the superimposed image tothe display controller 93. When the control unit 94 prohibits thesuperimposition, the superimposed image generation unit 924 outputs onlythe subject image subjected to the NR processing as the superimposedimage to the display controller 93.

The display controller 93 generates a video signal for display based onthe superimposed image output from the superimposed image generationunit 924 under the control of the control unit 94. Then, the displaycontroller 93 outputs the video signal to the display device 7 via thesecond transmission cable 8.

The control unit 94 is configured using, for example, a CPU or the like,and outputs a control signal via the first to third transmission cables6, 8, and 10 to control the operations of the light source device 3, thecamera head 5, and the display device 7 and control the whole operationof the control device 9. As illustrated in FIG. 2, the control unit 94includes a light source controller 941, an imaging controller 942, adetermination unit 943, a superimposition controller 944, and anotification controller 945.

The light source controller 941 outputs a control signal to the lightsource device 3 via the third transmission cable 10, and alternatelyswitches the state of the light source device 3 to the first and secondlight emission states in a time division manner. Here, the first lightemission state is a state in which white light is emitted. In addition,the second light emission state is a state in which near-infraredexcitation light is emitted.

The imaging controller 942 outputs a control signal to the camera head 5via the first transmission cable 6 and allows the imaging unit 52 toalternately capture the subject image and the fluorescent image in theimaging unit 52 in synchronization with switching timing of the state ofthe light source device 3.

The determination unit 943 determines whether or not at least one of thesubject and the observation device 100 moves from timing before timingat which one of the subject image and the fluorescent image is capturedby imaging unit 52 to the timing. In the first embodiment, thedetermination unit 943 executes first and second determinationprocessing.

Here, in the first determination processing, the determination unit 943determines whether or not a motion area exists in the current subjectimage CSC. The motion area is an area formed of pixels in which amongall the regions in the current subject image CSC, the first motionamount calculated by the motion amount calculation unit 922 exceeds aspecific threshold. Then, when there is the motion area in the currentsubject image CSC, the determination unit 943 determines that at leastone of the subject and the observation device 100 moves. On the otherhand, when there is no motion area in the current subject image CSC, thedetermination unit 943 determines that any of the subject and theobservation device 100 does not move.

In addition, in the second determination processing, the determinationunit 943 determines whether or not the motion area exists in the currentfluorescent image CFC. The motion area is an area formed of pixels inwhich among all the regions in the current fluorescent image CFC, thesecond motion amount calculated by the motion amount calculation unit922 exceeds a specific threshold. Then, when there is the motion area inthe current fluorescent image CFC, the determination unit 943 determinesthat at least one of the subject and the observation device 100 moves.On the other hand, when there is no motion area in the currentfluorescent image CFC, the determination unit 943 determines that any ofthe subject and the observation device 100 does not move.

When the determination unit 943 determines that at least one of thesubject and the observation device 100 moves, the superimpositioncontroller 944 causes the superimposed image generation unit 924 toprohibit the superimposition of the subject image and the fluorescentimage in all the regions.

If the determination unit 943 determines that at least one of thesubject and the observation device 100 moves, a notification controller945 notifies the notification unit 96 to notify information indicatingthe movement.

The input unit 95 is configured using operation devices such as a mouse,a keyboard, and a touch panel, and receives user operations by a usersuch as a doctor. Then, the input unit 95 outputs an operation signal tothe control unit 94 according to the user operation.

The notification unit 96 corresponds to a notification device. Thenotification unit 96 notifies the information indicating the movementunder the control of the notification controller 945. Examples of thenotification unit 96 include a light emitting diode (LED) that notifiesthe information according to lighting or blinking or a color whenlighting, a display device that displays the information, a speaker thatoutputs the information by voice, or the like. In the first embodiment,the notification unit 96 is configured to be provided inside the controldevice 9 but the notification unit 96 is not limited to thisconfiguration, and may be separately configured from the control device9.

The storage unit 97 stores a program executed by the control unit 94,information required for the processing of the control unit 94, and thelike.

Operation of Control Device

Next, the operation of the control device 9 described above will bedescribed.

FIG. 6 is a flowchart illustrating the operation of the control device9.

In the following description, a drug such as indocyanine green that isaccumulated in a lesion part such as a tumor is previously administeredto a subject.

First, the light source controller 941 controls the operation of thelight source device 3 and alternately switches the state of the lightsource device 3 to the first and second light emission states in a timedivision manner (step S1). Thereby, the white light and thenear-infrared excitation light are alternately irradiated to an insideof a living body.

After step S1, the imaging controller 942 causes the imaging unit 52 toalternately capture the subject image and the fluorescent image insynchronization with the switching timing of the state of the lightsource device 3 (steps S2 to S4). That is, when the state of the lightsource device 3 is in the first light emission state (step S2: Yes),that is, when the white light is irradiated into the living body, theimaging unit 52 captures the subject image reflected in the living body(step S3). On the other hand, when the state of the light source device3 is in the second light emission state (step S2: No), that is, when thenear-infrared excitation light is irradiated into the living body, theimaging unit 52 excites the drug such as the indocyanine green in theliving body and captures the fluorescent image emitted from the insideof the living body (step S4).

When the subject image is captured by the imaging unit 52 (when thecurrent subject image CSC is received by the communication unit 91), themotion amount calculation unit 922 sets the immediately previous subjectimage CSB and the current subject image CSC as the first processingtarget and performs the first motion amount calculation processing (stepS5).

On the other hand, when the fluorescent image is captured by the imagingunit 52 (when the current fluorescent image CFC is received by thecommunication unit 91), the motion amount calculation unit 922 sets theimmediately previous fluorescent image CFB and the current fluorescentimage CFC as the second processing target and performs the second motionamount calculation processing (step S6).

The determination unit 943 executes the first determination processingafter step S5, and executes the second determination processing afterstep S6 (step S7).

As a result of executing the first determination processing, when it isdetermined that there is no motion area in the current subject image CSC(it is determined that any of the subject and the observation device 100does not move) (step S7: No), the superimposed image generation unit 924executes the following processing (step S8).

That is, in step S8, the superimposed image generation unit 924generates the superimposed image by superimposing, between correspondingpixels in all the regions, the current subject image CSC and thefluorescent image immediately before the current subject image CSC intime series. Then, the superimposed image generation unit 924 outputsthe superimposed image to the display controller 93.

As a result of executing the second determination processing, when it isdetermined that there is no motion area in the current fluorescent imageCFC (it is determined that any of the subject and the observation device100 does not move) (step S7: No), the superimposed image generation unit924 executes the following processing (step S8).

That is, in step S8, the superimposed image generation unit 924generates the superimposed image by superimposing, between thecorresponding pixels in all the regions, the current fluorescent imageCFC and the subject image immediately before the current fluorescentimage CFC in time series. Then, the superimposed image generation unit924 outputs the superimposed image to the display controller 93.

After step S8, the display controller 93 generates the video signalbased on the superimposed image output from the superimposed imagegeneration unit 924, and outputs the video signal to the display device7 (step S9). Thus, the superimposed image is displayed on the displaydevice 7. Thereafter, the control device 9 returns to step S1.

On the other hand, as a result of executing the first determinationprocessing, when it is determined that there is the motion area in thecurrent subject image CSC (it is determined that at least one of thesubject and the observation device 100 moves) (step S7: Yes), thesuperimposition controller 944 causes the superimposed image generationunit 924 to prohibit the superimposition of the subject image and thefluorescent image in all the regions (step S10). Then, the superimposedimage generation unit 924 outputs the current subject image CSC as thesuperimposed image to the display controller 93.

In addition, as a result of executing the second determinationprocessing, similar to the case where it is determined that there is themotion area in the current fluorescent image CFC (it is determined thatat least one of the subject and the observation device 100 does notmove) (step S7: Yes), the superimposition controller 944 executes thestep S10. Then, the superimposed image generation unit 924 outputs, tothe display controller 93, the subject image immediately before thecurrent fluorescent image CFC in time series as the superimposed image.

After step S10, the display controller 93 generates the video signalbased on the superimposed image (subject image) output from thesuperimposed image generation unit 924, and outputs the video signal tothe display device 7 (step S11). Thus, the subject image is displayed onthe display device 7.

After step S11, the notification controller 925 causes the notificationunit 96 to notify the information indicating the movement (step S12).Thereafter, the control device 9 returns to step S1.

Specific Example of Displayed Image

Next, a specific example of the image displayed on the display device 7will be described.

FIG. 7 is a diagram illustrating a specific example of the imagedisplayed on the display device 7. Specifically, a part (a) of FIG. 7 isa view illustrating subject images CS1 to CS3 and fluorescent images CF1to CF3 captured by the camera head 5 at each timing t1 to t6 arranged intime series. A part (b) of FIG. 7 is a diagram illustrating one of thesubject image and the fluorescent image to be superimposed by thesuperimposed image generation unit 924. A part (c) of FIG. 7 is adiagram illustrating the image displayed on the display device 7.

In FIG. 7, for convenience of description, a mask area MA is notillustrated in the images CS1 to CS3, CF1 to CF3, and D1 to D6. Further,in the fluorescent images CF1 to CF3, the excitation region in which adrug such as indocyanine green in a living body is excited isrepresented in white, and the area other than the excitation region isrepresented in black. In addition, in the superimposed images D3, D4,and D6, the excitation regions are represented by an oblique line.

If the image captured by the camera head 5 is a subject image CS1(current subject image CSC) at initial timing t1 after the activation ofthe medical observation system 1, there is no subject image (immediatelyprevious subject image CSB) immediately before the subject image CS1 intime series. That is, the motion amount calculation unit 922 cannotperform the first motion amount calculation processing. Then, thesuperimposed image generation unit 924 outputs the subject image CS1 asthe superimposed image D1 to the display controller 93. Thereafter, thedisplay controller 93 generates a video signal based on the superimposedimage D1 (subject image CS1), and outputs the video signal to thedisplay device 7. As a result, as illustrated in the part (c) of FIG. 7,the superimposed image D1 (subject image CS1) is displayed on thedisplay device 7 at timing t1.

At timing t2 next to the timing t1, the image captured by the camerahead 5 is the fluorescent image CF1 (current fluorescent image CFC).Similar to the timing t1, even in the timing t2, there is no fluorescentimage (immediately previous fluorescent image CFB) immediately beforethe fluorescent image CF1 in time series. That is, the motion amountcalculation unit 922 cannot perform the second motion amount calculationprocessing. Then, the superimposed image generation unit 924 outputs, tothe display controller 93, the subject image CS1 immediately before thefluorescent image CF1 in time series as the superimposed image D2.Thereafter, the display controller 93 generates a video signal based onthe superimposed image D2 (subject image CS1), and outputs the videosignal to the display device 7. As a result, as illustrated in the part(c) of FIG. 7, the superimposed image D2 (subject image CS1) isdisplayed on the display device 7 at timing t2.

At timing t3 next to the timing t2, the image captured by the camerahead 5 is the subject image CS2 (current subject image CSC). At thetiming t3, the motion amount calculation unit 922 performs the firstmotion amount calculation processing on, as the first processing target,the subject image CS2 (current subject image CSC) and the subject imageCS1 (immediately previous subject image CSB) immediately before thesubject image CS2 in time series (step S5). Here, there is no motionarea in the subject image CS2 (current subject image CSC). Therefore, inthe first determination processing (step S7), it is determined as “No”.Then, the superimposed image generation unit 924 generates asuperimposed image D3 by superimposing, between the corresponding pixelsin all the regions, the subject image CS2 (current subject image CSC)and the fluorescent image CF1 (the part (b) of FIG. 7) immediatelybefore the subject image CS2 in time series and outputs the superimposedimage D3 to the display controller 93 (step S8). Thereafter, the displaycontroller 93 generates a video signal based on the superimposed imageD3, and outputs the video signal to the display device 7 (step S9). As aresult, as illustrated in the part (c) of FIG. 7, the superimposed imageD3 is displayed on the display device 7 at timing t3.

At timing t4 next to the timing t3, the image captured by the camerahead 5 is the fluorescent image CF2 (current fluorescent image CFC). Atthe timing t4, the motion amount calculation unit 922 performs thesecond motion amount calculation processing on, as the second processingtarget, the fluorescent image CF2 (current fluorescent image CFC) andthe fluorescent image CF1 (immediately previous fluorescent image CFB)immediately before the fluorescent image CF2 in time series (step S6).Here, there is no motion area in the fluorescent image CF2 (currentfluorescent image CFC). Therefore, in the second determinationprocessing (step S7), it is determined as “No”. Then, the superimposedimage generation unit 924 generates a superimposed image D4 bysuperimposing, between the corresponding pixels in all the regions, thefluorescent image CF2 (current fluorescent image CFC) and the subjectimage CS2 (the part (b) of FIG. 7) immediately before the fluorescentimage CF2 in time series and outputs the superimposed image D4 to thedisplay controller 93 (step S8). Thereafter, the display controller 93generates a video signal based on the superimposed image D4, and outputsthe video signal to the display device 7 (step S9). As a result, asillustrated in the part (c) of FIG. 7, the superimposed image D4 isdisplayed on the display device 7 at timing t4.

At timing t5 next to the timing t4, the image captured by the camerahead 5 is a subject image CS3 (current subject image CSC). At the timingt5, the motion amount calculation unit 922 performs the first motionamount calculation processing, as the first processing target, thesubject image CS3 (current subject image CSC) and the subject image CS2(immediately previous subject image CSB) immediately before the subjectimage CS3 in time series (step S5). Here, a motion area AM (the part (a)of FIG. 7) exists in the subject image CS3 (current subject image CS3).Therefore, in the first determination processing (step S7), it isdetermined as “Yes”. Then, the superimposition controller 944 causes thesuperimposed image generation unit 924 to prohibit the superimpositionof the subject image and the fluorescent image in all the regions (stepS10). In addition, the superimposed image generation unit 924 outputsthe subject image CS3 as the superimposed image D5 to the displaycontroller 93. Thereafter, the display controller 93 generates a videosignal based on the superimposed image D5 (subject image CS3), andoutputs the video signal to the display device 7 (step S11). As aresult, as illustrated in the part (c) of FIG. 7, the superimposed imageD5 (subject image CS3) is displayed on the display device 7 at timingt5. In addition, the notification unit 96 notifies the informationindicating the movement (step S12).

At timing t6 next to the timing t5, the image captured by the camerahead 5 is a fluorescent image CF3 (current fluorescent image CFC). Atthe timing t6, the motion amount calculation unit 922 performs thesecond motion amount calculation processing on, as the second processingtarget, the fluorescent image CF3 (current fluorescent image CFC) andthe fluorescent image CF2 (immediately previous fluorescent image CFB)immediately before the fluorescent image CF3 in time series (step S6).Here, there is no motion area in the fluorescent image CF3 (currentfluorescent image CFC). Therefore, in the second determinationprocessing (step S7), it is determined as “No”. Then, the superimposedimage generation unit 924 generates a superimposed image D6 bysuperimposing, between the corresponding pixels in all the regions, thefluorescent image CF3 (current fluorescent image CFC) and the subjectimage CS3 (the part (b) of FIG. 7) immediately before the fluorescentimage CF3 in time series and outputs the superimposed image D6 to thedisplay controller 93 (step S8). Thereafter, the display controller 93generates a video signal based on the superimposed image D6, and outputsthe video signal to the display device 7 (step S9). As a result, asillustrated in the part (c) of FIG. 7, the superimposed image D6 isdisplayed on the display device 7 at timing t6. In addition, thenotification unit 96 stops the information indicating the movement.

According to the first embodiment described above, the following effectsare obtained.

The control device 9 according to the first embodiment determineswhether or not at least one of the subject and the observation device100 moves from timing before timing at which one of the subject imageand the fluorescent image is captured to the timing. Then, when it isdetermined that both the subject and the observation device 100 do notmove, the control device 9 generates the superimposed image bysuperimposing the subject image and the fluorescent image between thecorresponding pixels in all the regions. On the other hand, when it isdetermined that at least one of the subject and the observation device100 moves, the control device 9 does not superimpose the subject imageand the fluorescent image.

Therefore, even when at least one of the subject and the observationdevice 100 moves, the display device 7 does not display the superimposedimage in which the corresponding observed regions of the subject imageand the fluorescent image are shifted from each other. That is, there isa possibility that the doctor does not recognize, as a lesion part, asite at which no lesion part is actually present, from the superimposedimage displayed on the display device 7. Therefore, according to thecontrol device 9 according to the first embodiment, the convenience maybe improved.

Further, the control device 9 according to the first embodimentdetermines, based on the first and second motion amounts calculated inthe first and second motion amount calculation processing, whether ornot at least one of the subject and the observation device 100 moves.

That is, since the determination on whether or not at least one of thesubject and the observation device 100 moves may be executed by theimage processing of the subject image or the fluorescent image, theobservation device 100 does not need to be equipped with devices such asan acceleration sensor or a gyro sensor. Therefore, the structure of themedical observation system 1 may be simplified.

In particular, in the first motion amount calculation processing, twosubject images are set as the first processing target. In addition,similarly in the second motion amount calculation processing, twofluorescent images are set as the second processing target.

Therefore, for example, compared with the configuration in which themotion amount calculation processing is performed on the subject imageand the fluorescent image, the motion amount may be calculated with highaccuracy, and it is possible to determine whether or not at least one ofthe subject and the observation device 100 moves with high accuracy.

Further, in the control device 9 according to the first embodiment, thefirst processing target used in the first motion amount calculationprocessing is set as two subject images consecutive in time series. Inaddition, the second processing target used in the second motion amountcalculation processing is set as two fluorescent images consecutive intime series.

Therefore, it is possible to appropriately determine whether or not atleast one of the subject and the observation device 100 moves fromtiming immediately before the timing at which the current subject imageCSC or the current fluorescent image CFC is captured to the timing.

Further, in the first embodiment, the observation device 100 alternatelycaptures the subject image and the fluorescent image to alternatelygenerate the subject image and the fluorescent image sequentially. Inaddition, the control device 9 superimposes the subject image and thefluorescent image which are consecutive in time series to generate thesuperimposed image.

Therefore, the same superimposed image is not consecutively displayedfor each frame, and the superimposed image (superimposed images D3 to D6in the example of FIG. 7) obtained by capturing the latest state of thesubject may be sequentially displayed for each frame.

Here, the subject image is an image obtained by irradiating the subjectwith white light and capturing the subject image reflected from thesubject. Therefore, the subject image is an image that is easy torecognize the entire shape of a subject's mucosa and the like. On theother hand, the fluorescent image is an image obtained by irradiatingthe subject with near-infrared excitation light, exciting a drug such asindocyanine green accumulated in a lesion part in the subject, andcapturing the fluorescent image emitted from the subject. Therefore, thefluorescent image is an image that is hard to recognize the entire shapeof a subject's mucosa and the like.

Here, in the medical observation system 1 according to the firstembodiment, when it is determined that at least one of the subject imageand the observation device 100 moves, the subject image is displayed onthe display device 7.

That is, when at least one of the subject and the observation device 100moves, the image displayed on the display device 7 does not disappear,and the subject image that easily recognizes the entire shape of thesubject's mucosa or the like is displayed on the display device 7.Therefore, a doctor may continuously check the state of the subject.Therefore, it is possible to further improve the convenience.

In addition, when it is determined that at least one of the subject andthe observation device 100 moves, the control device 9 according to thefirst embodiment notifies the notification unit 96 of the informationindicating the movement.

For this reason, when the display is switched from the immediatelyprevious superimposed image (superimposed image D4 in the example ofFIG. 7) to the current superimposed image (superimposed image D5 in theexample of FIG. 7), a doctor and the like may recognize, based on theinformation, the reason in which the excitation region (represented by adiagonal line in the example of FIG. 7) disappears.

Therefore, it is possible to improve the convenience.

Second Embodiment

Next, a second embodiment will be described.

In the following description, the same reference numerals are given tothe same components as those of the above-described first embodiment,and a detailed description thereof will be omitted or simplified.

In the second embodiment, functions of a superimposed image generationunit 924 and a superimposition controller 944 are different from thoseof the first embodiment described above. The functions of thesuperimposed image generation unit 924 and the superimpositioncontroller 944 according to the second embodiment will be described inthe following “operation of control device 9”.

Operation of Control Device

FIG. 8 is a flowchart illustrating an operation of a control device 9according to the second embodiment.

In the operation of the control device 9 according to the secondembodiment, as illustrated in FIG. 8, steps S13 to S15 are performedinstead of steps S10 and S11 with respect to the operation of thecontrol device 9 described in the first embodiment described above. Forthis reason, only steps S13 to S15 will be described below.

As a result of performing the first determination processing, if it isdetermined that there is the motion area in the current subject imageCSC (step S7: Yes), the superimposition controller 944 causes thesuperimposed image generation unit 924 to prohibit the superimpositionin the motion area of the subject image and the fluorescent image, andpermit the superimposition in an area other than the motion area (stepS13). Thereafter, the superimposed image generation unit 924 generatesthe superimposed image by superimposing, between corresponding pixels inthe area other than the motion area, the subject image CSC and thefluorescent image immediately before the current subject image CSC intime series (step S14). In the superimposed image, the region (motionarea) whose superimposition is prohibited by the superimpositioncontroller 944 is configured by a corresponding area in the currentsubject image CSC. Then, the superimposed image generation unit 924outputs the superimposed image to the display controller 93.

In addition, as a result of executing the second determinationprocessing, similar to the case where it is determined that there is themotion area in the current fluorescent image CFC (step S7: Yes), thesuperimposition controller 944 executes the step S13. Thereafter, thesuperimposed image generation unit 924 generates the superimposed imageby superimposing, between corresponding pixels in the area other thanthe motion area, the current fluorescent image CFC and the subject imageimmediately before the current fluorescent image CFC in time series(step S14). In the superimposed image, the region (motion area) whosesuperimposition is prohibited by the superimposition controller 944 isconfigured by a corresponding area in the immediately previous currentsubject image to the current fluorescent image CFC in time series. Then,the superimposed image generation unit 924 outputs the superimposedimage to the display controller 93.

After step S14, the display controller 93 generates the video signalbased on the superimposed image output from the superimposed imagegeneration unit 924, and outputs the video signal to the display device7 (step S15). Thus, the superimposed image is displayed on the displaydevice 7. Thereafter, the control device 9 performs step S12.

Specific Example of Displayed Image

Next, a specific example of the image displayed on the display device 7will be described.

FIG. 9 is a diagram illustrating a specific example of the imagedisplayed on the display device 7. FIG. 9 is a diagram corresponding toFIG. 7. Further, in the superimposed image D5, similarly to thesuperimposed images D3, D4, and D6, an excitation region in which a drugsuch as indocyanine green in a living body is excited is represented bya diagonal line.

Hereinafter, at each timing t1 to t6 arranged in time series, the casewhere subject images CS1 to CS3 and fluorescent images CF1 to CF3identical to the image (the part (a) of FIG. 7) described in the firstembodiment described above are captured by a camera head 5 will bedescribed.

Compared with the first embodiment described above, in the secondembodiment, different images are displayed only at timing t5. For thisreason, only the timing t5 will be described below.

At the timing t5, the image captured by the camera head 5 is the subjectimage CS3 (current subject image CSC). At the timing t5, the motionamount calculation unit 922 performs the first motion amount calculationprocessing, as the first processing target, the subject image CS3(current subject image CSC) and the subject image CS2 (immediatelyprevious subject image CSB) immediately before the subject image CS3 intime series (step S5). Here, a motion area AM (a part (a) of FIG. 9)exists in the subject image CS3 (current subject image CS3). Therefore,in the first determination processing (step S7), it is determined as“Yes”. Then, the superimposition controller 944 causes the superimposedimage generation unit 924 to prohibit the superimposition in the motionarea AM of the subject image and the fluorescent image (step S13). Inaddition, the superimposed image generation unit 924 generates asuperimposed image D5 by superimposing, between the corresponding pixelsin the area other than the motion area AM, the subject image CS3(current subject image CSC) and the fluorescent image CF2 immediatelybefore the subject image CS3 in time series and outputs the superimposedimage D5 to the display controller 93 (step S14). In the superimposedimage D5, the motion area AM is configured by the corresponding area inthe current subject image CS3. Thereafter, the display controller 93generates a video signal based on the superimposed image D5, and outputsthe video signal to the display device 7 (step S15). As a result, asillustrated in a part (c) of FIG. 9, the superimposed image D5 isdisplayed on the display device 7 at timing t5. In addition, thenotification unit 96 notifies the information indicating the movement(step S12).

If it is determined that at least one of the subject and the observationdevice 100 moves as in the second embodiment described above, even inthe case of the configuration in which the superimposition of thesubject image and the fluorescent image in the motion area is prohibitedand the superimposition in the area other than the motion area ispermitted, the same effects as those in the first embodiment areobtained.

Other Embodiments

Although the embodiments for carrying out the present disclosure havebeen described so far, the present disclosure should not be limited onlyto the first and second embodiments described above.

The above-described embodiments 1 and 2 determine based on the first andsecond motion amounts calculated by the first and second motion amountcalculation processing whether or not at least one of the subject andthe observation device 100 moves, but are not limited thereto. Forexample, a device such as an acceleration sensor or a gyro sensor ismounted on the observation device 100, and it is determined based on theacceleration or angular velocity detected by the device such as theacceleration sensor or the gyro sensor whether or not the observationdevice 100 moves.

In the first and second embodiments described above, the first andsecond motion amounts are calculated by the block matching method or thegradient method, but the first and second embodiments are not limitedthereto.

For example, pixel levels of two subject images captured at differenttimings are compared between the corresponding pixels. Then, the changeamount of the pixel level may be calculated as the first motion amount.Similarly, the pixel levels of two fluorescent images captured atdifferent timings are compared between the corresponding pixels. Then,the change amount of the pixel level may be calculated as the secondmotion amount. At this time, instead of the configuration in which thefirst and second motion amounts may each be calculated for each pixel,the first and second motion amounts may each be calculated for eachpixel group (area) including a plurality of pixels. The same applies tothe first and second embodiments described above.

Note that, as the pixel level, if the subject image or the fluorescentimage is an image before demosaic processing, component information(pixel value) of any of read (R), green (G), and blue (B) correspondingto each filter group of R, G, and B constituting a color filter providedon the imaging surface of the image sensor (imaging unit 52) may beexemplified. Further, as the pixel level, if the subject image or thefluorescent image is an image after the demosaic processing, a luminancevalue according to the RGB value (pixel value) or a Y signal (luminancesignal) may be exemplified.

In the first and second embodiments described above, the same type oftwo subject images or the same type of two fluorescent images areadopted as processing targets used in the motion amount calculationprocessing, but the first and second embodiments are not limitedthereto, and the subject image and the fluorescent image may be adoptedas the processing targets. That is, the motion amount may be calculatedby comparing the subject image with the fluorescent image.

In the first and second embodiments described above, although twosubject images consecutive in time series are set to the firstprocessing target, the first and second embodiments are not limitedthereto, and two subject images not consecutive in time series may beset to the first processing target. That is, the current subject imageCSC and the subject image captured by the camera head 5 four framesbefore with respect to the current subject image CSC may be adopted asthe first processing target.

Similarly, in the first and second embodiments described above, althoughtwo fluorescent images consecutive in time series are set to the secondprocessing target, the first and second embodiments are not limitedthereto, and two fluorescent images not consecutive in time series maybe set to the second processing target. That is, the current fluorescentimage CFC and the fluorescent image captured by the camera head 5 fourframes before with respect to the current fluorescent image CFC may beadopted as the second processing target.

In the first and second embodiments described above, a configuration maybe adopted in which only one of the first and second motion amountcalculation processing (first and second determination processing) isperformed.

In the first and second embodiments described above, when the subjectimage and the fluorescent image are superimposed, the current subjectimage CSC and the fluorescent image immediately before the currentsubject image CSC in time series are superimposed, but the first andsecond embodiments are not limited thereto. For example, the currentsubject image CSC and the fluorescent image immediately after thecurrent subject image CSC in time series may be superimposed.

Similarly, in the first and second embodiments described above, when thesubject image and the fluorescent image are superimposed, the currentfluorescent image CFC and the subject image immediately before thecurrent fluorescent image CFC in time series are superimposed, but thefirst and second embodiments are not limited thereto. For example, thecurrent fluorescent image CFC and the subject image immediately afterthe current fluorescent image CFC in time series may be superimposed.

In the first and second embodiments described above, the subject imageand the fluorescent image are alternately captured, and the subjectimage and the fluorescent image are alternately generated for eachframe, but the first and second embodiments are not limited thereto. Forexample, a configuration may be adopted in which at least one of thesubject image and the fluorescent image is consecutively captured, andat least one of the subject image and the fluorescent image isconsecutively generated for several frames.

In the first and second embodiments described above, step S12 may beomitted. Further, in the first and second embodiments described above,steps S8, S9, and S12 may be performed when “Yes” is determined in stepS7.

In the first and second embodiments described above, the configurationof the light source device 3 is not limited to the configurationdescribed in the first and second embodiments described above, and inthe case of a configuration capable of emitting the white light and thenear-infrared excitation light in a time division manner, otherconfigurations may be adopted.

Similarly, in the first and second embodiments described above, theconfiguration of the imaging unit 52 is not limited to the configurationdescribed in the first and second embodiments described above, and inthe case of a configuration capable of generating the subject image andthe fluorescent image, the configuration using two image sensors may beadopted.

In the first and second embodiments described above, the white light isused when generating the subject image, but the first and secondembodiments are not limited thereto, and light in another specificwavelength band may be adopted.

Similarly, in the first and second embodiments described above, thenear-infrared excitation light is used when generating the fluorescentimage, but the first and second embodiments are not limited thereto, andlight in another specific wavelength band may be adopted.

In the first and second embodiments described above, the medical imageprocessing apparatus is mounted on the medical observation system 1 inwhich the insertion unit 2 is constituted by a rigid endoscope, but thefirst and second embodiments are not limited thereto. For example, themedical image processing apparatus may be mounted on the medicalobservation system in which the insertion unit 2 is constituted by aflexible endoscope. In addition, the medical image processing apparatusmay be mounted on the medical observation system such as a surgicalmicroscope (for example, see JP 2016-42981 A) for enlarging andobserving a predetermined visual field area in a subject (in a livingbody) or a subject surface (surface of a living body).

In the first and second embodiments described above, the configurationof a part of the camera head 5 or the configuration of a part of thecontrol device 9 may be provided in, for example, the connector CN1 orthe connector CN2.

According to the medical image processing apparatus and the medicalobservation system, the convenience may be improved.

Although the disclosure has been described with respect to specificembodiments for a complete and clear disclosure, the appended claims arenot to be thus limited but are to be construed as embodying allmodifications and alternative constructions that may occur to oneskilled in the art that fairly fall within the basic teaching herein setforth.

What is claimed is:
 1. A medical image processing apparatus connected toan observation device that generates a subject image by capturing thesubject image reflected from a subject and generates a fluorescent imageby capturing a fluorescent image emitted from the subject at differenttiming from the subject image, the medical image processing apparatuscomprising: a superimposed image generation unit configured to generatea superimposed image by superimposing the subject image and thefluorescent image in areas corresponding to each other; a determinationunit configured to determine whether or not at least one of the subjectand the observation device moves from timing before timing at which oneof the subject image and the fluorescent image is captured to thetiming; and a superimposition controller configured to cause thesuperimposition image generation unit to prohibit a superimposition inan area of at least a part of the subject image and the fluorescentimage when the determination unit determines that at least one of thesubject and the observation device moves.
 2. The medical imageprocessing apparatus according to claim 1, wherein the observationdevice sequentially generates the subject image by capturing the subjectimage at different timings and sequentially generates the fluorescentimage by capturing the fluorescent image at different timings, themedical image processing apparatus further includes a motion amountcalculation unit configured to set two subject images generated by theobservation device to a first processing target, and perform at leastone of first motion amount calculation processing of calculating a firstmotion amount from the one subject image for each area of the othersubject image and second motion amount calculation processing ofcalculating a second motion amount from the one fluorescent image foreach area of the other fluorescent image, and the determination unitperforms at least one of first determination processing of determiningbased on the first motion amount whether or not at least one of thesubject and the observation device moves and second determinationprocessing of determining based on the second motion amount whether ornot at least one of the subject and the observation device moves.
 3. Themedical image processing apparatus according to claim 2, wherein thefirst processing target is the two subject images consecutive in timeseries, and the second processing target is the two fluorescent imagesconsecutive in time series.
 4. The medical image processing apparatusaccording to claim 3, wherein the observation device alternativelygenerates the subject image and the fluorescent image sequentially byalternately capturing the subject image and the fluorescent image, thesuperimposed image generation unit generates the superimposed image bysuperimposing the subject image and the fluorescent image consecutive intime series, the motion amount calculation unit performs both the firstmotion amount calculation processing and the second motion amountcalculation processing, and the determination unit performs both thefirst determination processing and the second determination processing.5. The medical image processing apparatus according to claim 2, whereinin the first determination processing, when a motion area in which thefirst motion amount exceeds a specific threshold value exists in thesubject image, it is determined that at least one of the subject and theobservation device moves, and in the second determination processing,when a motion area in which a second motion amount exceeds a specificthreshold value exists in the fluorescent image, it is determined thatat least one of the subject and the observation device moves.
 6. Themedical image processing apparatus according to claim 5, wherein thesuperimposition controller causes the superimposed image generation unitto prohibit the superimposition in the motion area of the subject imageand the fluorescent image and permit the superimposition in an areaother than the motion area when the determination unit determines thatat least one of the subject and the observation device moves.
 7. Themedical image processing apparatus according to claim 5, wherein thesuperimposition controller causes the superimposed image generation unitto prohibit the superimposition of the subject image and the fluorescentimage when the determination unit determines that at least one of thesubject and the observation device moves.
 8. The medical imageprocessing apparatus according to claim 1, wherein the superimposedimage generation unit generates the superimposed image by setting anarea where the superimposition is prohibited by the superimpositioncontroller to the corresponding area in the subject image.
 9. A medicalobservation system, comprising: an observation device configured togenerate a subject image by capturing the subject image reflected from asubject and generates a fluorescent image by capturing a fluorescentimage emitted from the subject at different timing from the subjectimage; the medical image processing device according to claim 1 that isconnected to the observation device and processes the subject image andthe fluorescent image; and a display device configured to display asuperimposed image generated by the medical image processing device. 10.A medical image processing apparatus connected to an observation devicethat generates a subject image by capturing the subject image reflectedfrom a subject and generates a fluorescent image by capturing afluorescent image emitted from the subject at different timing from thesubject image, the medical image processing apparatus comprising: asuperimposed image generation unit configured to generate a superimposedimage by superimposing the subject image and the fluorescent image inareas corresponding to each other; a determination unit configured todetermine whether or not at least one of the subject and the observationdevice moves from timing before timing at which at least one of thesubject image and the fluorescent image is captured to the timing; and anotification controller configured to notify a notification device ofinformation indicating the motion when the determination unit determinesthat at least one of the subject and the observation device moves.
 11. Amedical observation system, comprising: an observation device configuredto generate a subject image by capturing the subject image reflectedfrom a subject and generates a fluorescent image by capturing afluorescent image emitted from the subject at different timing from thesubject image; the medical image processing device according to claim 10that is connected to the observation device and processes the subjectimage and the fluorescent image; and a display device configured todisplay a superimposed image generated by the medical image processingdevice.